At least 21 people have been killed, over 1,500 others injured and at least seven are still missing in Niigata Prefecture after a series of powerful earthquakes rocked northern Japan Saturday evening, a survey by Kyodo News Service showed Sunday.  

Rescue workers have been mobilized to search for the missing people, while efforts to restore power, water and gas supplies are underway following the first magnitude 6.8 quake that struck Ojiya, Niigata Prefecture, 200 kilometers northwest of Tokyo, just before 6 PM (0900 GMT) Saturday.

Up to 68,000 people have been evacuated and many people remain stranded and anxious with communications and transportation infrastructure badly damaged in the province, while a few fresh strong jolts and countless weak after shocks were felt throughout the day.

The full extent of damage from the quake remains unknown but at least 76 homes collapsed either completely or partially, landslides occurred in 37 places, and roads were damaged or caved in at 211 locations in Niigata as of Sunday afternoon, Japan National Police Agency said.

The government established an emergency headquarters on Sunday morning and sent an investigation team headed by Disaster Management Minister Yoshitaka Murata to assess the damage.

This is the first time that the death toll from a quake has been in double digits since the Great Hanshin Earthquake in January 1995, which killed around 6,400 in the much more densely populated Kobe city and its vicinity.

A powerful earthquake measuring a preliminary magnitude of 6.8 hit at 5:56 PM (0856 GMT) Saturday with its epicenter 20 kilometers underground in the Chuetsu region in central Niigata. It is the first and strongest in the series of earthquakes over the evening, according to the Japan Meteorological Agency.

The agency said more than 270 perceptible quakes took place Sunday including about 30 strong tremors, with an intensity of 4 or above on the Japanese seismic intensity scale of 7.

The meteorological agency has said aftershocks are continuing in the area and warned of possible strong intensity-6 quakes and landslides due to loose ground caused by massive rainfall from Typhoon Tokage last week that swept the Japanese archipelago.

The agency named the quake the "Niigata-ken Chuetsu (central Niigata Prefecture) Earthquake" in recognition of its significant devastation. It customarily gives a name to major earthquakes.

(Xinhua News Agency October 25, 2004)